Yes, many people in your position can indeed get that mortgage and buy your house. But, it's a really big mortgage and a lot of people don't want to take that

Yes, many people in your position can indeed get that mortgage and buy your house. But, it's a really big mortgage and a lot of people don't want to take that big of a financial risk for what is likely a small, average looking home on a small lot in the Bay Area. If you really, really want that house, then sure you can make it work (and more power to you, I hope you love it)! If you value financial freedom and not being tied down by debt, then the deal is not so good.